1. Field of the Invention
This invention relates to a conveyor system for transporting, storing and regulating the flow rate of articles exiting the conveyor. It is more particularly directed to such a conveyor system for use with elongated articles that furnish surfaces on which the articles may roll, such as camshafts and the like, when they are transferred between support rails that are cyclically raised and lowered.
2. Description of the Prior Art
During the highly automated, high volume production of parts requiring several forming processes during their manufacture, it is essential that the parts progress along a process line that carries the articles from the raw stock condition to the machines that form the parts to their final shape. Generally, several forming stations are required for such an operation, and typically an automatically controlled conveyor will transport the articles between the stations.
The amount of time required at each work station to complete its operation differs among the various stations of the process line. Whereas one machine performing an initial operation on the article will complete its work within a brief period of time, a later operation might require a substantially greater period of time. In such a case, a conveyor that transports articles between two such forming machines, even one that extends for perhaps 100 feet between the work stations, will become filled with articles awaiting admittance to the slower work station. A conveyor having only the ability to advance the articles along its length would require means for removing articles from the conveyor, storing them, and later returning them to the conveyor for transport to the succeeding work stations of the manufacturing process. A conveyor operating in a high volume automatically controlled assembly line will require some capacity for storing articles to adjust for the different process steps of the machining operation. In addition, when articles have completed their travel along the conveyor, they must be held ready for introduction to the next work station at a rate that is compatible with the ability of that station to receive them.
Conveyors suitable for operating in such an environment have been developed for imparting a step-by-step forward motion to workpieces whereby they are advanced a short distance at a time along the conveyor length. Examples of conveyors wherein the transported articles are moved forward incrementally only as preceding workpieces are removed from forward positions on a toggle are described in U.S. Pat. No. 2,948,386 and Polish Pat. No. 51,850. Still another conveyor operating on the incremental forward motion principle but using a reciprocating vertical motion to lift the conveyed articles from a stationary support rail to a movable support rail has been disclosed in U.S. Pat. No. 3,623,600. Each of the conveyors described in these patents requires some means for sensing the presence of an article in a forward position on the conveyor which presence will operate to prevent forward motion of succeeding workpieces. Generally, the advancement of the articles results because of a pivoting mount of the carrier members of the conveyor, which upon pivoting move the workpieces forward onto the next toggle member.